Over recent decades, business, social and other interactions have begun throwing off increasingly-detailed data, and these data have been collected, aggregated and saved with increasing diligence. Also, all forms of media are increasingly likely to originate in, or at least pass through, a digital phase, so they can also be stored, aggregated, searched, manipulated and retrieved. Despite the vanishingly small apparent value of many individual data records, aggregating, indexing and providing access to data can be a remarkably profitable line of business.
Those who provide data (“content”) over the Internet have a strong interest—financially and otherwise—in ensuring that the content is used only in ways that the content provider permits. For example, a content provider may license its data for its customers' personal use only. However, a malicious party may acquire such a license but then proceed to download every available piece of content from the provider, not using it for his own use but instead republishing and/or reselling the content on the malicious party's own web site as his own. (Such downloading is sometimes called “screen scraping” or simply “scraping.”) This harms the original content provider by creating a competing source for the same content—material that was effectively stolen from the original provider.
After-the-fact revocation of the malicious party's license is an inadequate solution, since once the content has been downloaded, it may be difficult or impossible to stop its further spread. In particular, some data to which access may be provided via license, may not be subject to copyright claims by the data provider—the provider's “value add” is in collecting and indexing the data. A malicious user who violates his license to harvest the entire database may not be liable for any legal claims beyond breach of contract, and in any case, the user may be beyond the reach of legal process available to the content provider, or may simply be judgment-proof.
Techniques to detect and frustrate or thwart access to data that does not comply with the license under which access is offered can be of value in this field.